Oracle分析函数RANK()|ROW_NUMBER()|LAG()使用详解 ROW_NUMBER()函数: row_number()和rownum差不多,功能更强一点(可以在各个分组内从1开时排序),效率更高(?效率貌更差些,实际测验时)。 ROW_NUMBER()的使用方法: ROW_NUMBER() OVER (PARTITION BY C
Oracle分析函数RANK()|ROW_NUMBER()|LAG()使用详解
ROW_NUMBER()函数:
row_number()和rownum差不多,功能更强一点(可以在各个分组内从1开时排序),效率更高(?效率貌似更差些,实际测验时)。
ROW_NUMBER()的使用方法:
ROW_NUMBER() OVER (PARTITION BY COL1 ORDER BY COL2)
详细说明:
根据COL1分组
在分组内部根据 COL2排序
而这个值就表示每组内部排序后的顺序编号(组内连续的唯一的)
- ROW_NUMBER()语法如下:
- 1、row_number() over(order by column desc)先对列column按照降序,再为每条记录返回一个序列号:
- SELECT D.*, ROW_NUMBER() OVER(ORDER BY D.R_OPATE_NUM DESC) AS INX FROM REPORT_DATA D
ROW_NUMBER()语法如下: 1、row_number() over(order by column desc)先对列column按照降序,再为每条记录返回一个序列号: SELECT D.*, ROW_NUMBER() OVER(ORDER BY D.R_OPATE_NUM DESC) AS INX FROM REPORT_DATA D
[sql] view plaincopyprint?
- 2、row_number() over(partition by column1 order by column2 asc) 先按照column1分组,再对分组后的数据进行以column2升序排列
- select personalid,ct_smp_type,row_number() over(partition by personalid order by ct_smp_type asc) rn from neogoodsrule
- 语法1的具体实例:获取前100名人员的排名信息,如下
2、row_number() over(partition by column1 order by column2 asc) 先按照column1分组,再对分组后的数据进行以column2升序排列 select personalid,ct_smp_type,row_number() over(partition by personalid order by ct_smp_type asc) rn from neogoodsrule 语法1的具体实例:获取前100名人员的排名信息,如下
[sql] view plaincopyprint?
<span>name</span><span>=</span><span>"code"</span><span>></span><span>WITH</span><span> REPORT_DATA </span><span>AS</span><span> </span>
- (SELECT DW.DWID,DW.DWMC,JY.JYXM,JY.JH,RMPC.R_OPATE_NUM
- FROM REPORT_MONTH_PERSON_COUNT RMPC,JWT_JYXX JY,T_DWXX DW
- WHERE RMPC.JYID = JY.JYUSERID
- AND JY.SSDW = DW.DWID
- AND RMPC.R_YEAR = 2013
- AND RMPC.R_MONTH = 6
- AND JY.SSDW LIKE '4102%'
- ORDER BY RMPC.R_OPATE_NUM DESC)
- SELECT B.*
- FROM (SELECT D.*, ROW_NUMBER() OVER(ORDER BY D.R_OPATE_NUM DESC) AS INX
- FROM REPORT_DATA D
- ) B
- WHERE B.INX
-
ORDER BY B.INX
<div class="dp-highlighter bg_sql"> <div class="bar"><div class="tools"> <strong>[sql]</strong> <a target="_blank" class="ViewSource" title="view plain" href="http://blog.csdn.net/liqingan880102/article/details/9924257#">view plain</a><a target="_blank" class="CopyToClipboard" title="copy" href="http://blog.csdn.net/liqingan880102/article/details/9924257#">copy</a><a target="_blank" class="PrintSource" title="print" href="http://blog.csdn.net/liqingan880102/article/details/9924257#">print</a><a target="_blank" class="About" title="?" href="http://blog.csdn.net/liqingan880102/article/details/9924257#">?</a> </div></div> <ol class="dp-sql"> <li class="alt"><span><span class="keyword">WITH</span><span> REPORT_DATA </span><span class="keyword">AS</span><span> </span></span></li> <li> <span> (</span><span class="keyword">SELECT</span><span> DW.DWID,DW.DWMC,JY.JYXM,JY.JH,RMPC.R_OPATE_NUM </span> </li> <li class="alt"> <span> </span><span class="keyword">FROM</span><span> REPORT_MONTH_PERSON_COUNT RMPC,JWT_JYXX JY,T_DWXX DW </span> </li> <li> <span> </span><span class="keyword">WHERE</span><span> RMPC.JYID = JY.JYUSERID </span> </li> <li class="alt"> <span> </span><span class="op">AND</span><span> JY.SSDW = DW.DWID </span> </li> <li> <span> </span><span class="op">AND</span><span> RMPC.R_YEAR = 2013 </span> </li> <li class="alt"> <span> </span><span class="op">AND</span><span> RMPC.R_MONTH = 6 </span> </li> <li> <span> </span><span class="op">AND</span><span> JY.SSDW </span><span class="op">LIKE</span><span> </span><span class="string">'4102%'</span><span> </span> </li> <li class="alt"> <span> </span><span class="keyword">ORDER</span><span> </span><span class="keyword">BY</span><span> RMPC.R_OPATE_NUM </span><span class="keyword">DESC</span><span>) </span> </li> <li> <span></span><span class="keyword">SELECT</span><span> B.* </span> </li> <li class="alt"> <span></span><span class="keyword">FROM</span><span> (</span><span class="keyword">SELECT</span><span> D.*, ROW_NUMBER() OVER(</span><span class="keyword">ORDER</span><span> </span><span class="keyword">BY</span><span> D.R_OPATE_NUM </span><span class="keyword">DESC</span><span>) </span><span class="keyword">AS</span><span> INX </span> </li> <li> <span> </span><span class="keyword">FROM</span><span> REPORT_DATA D </span> </li> <li class="alt"><span> ) B </span></li> <li> <span></span><span class="keyword">WHERE</span><span> B.INX </span> </li> <li class="alt"> <span></span><span class="keyword">ORDER</span><span> </span><span class="keyword">BY</span><span> B.INX </span> </li> </ol> </div><pre class='brush:php;toolbar:false;'>WITH REPORT_DATA AS (SELECT DW.DWID,DW.DWMC,JY.JYXM,JY.JH,RMPC.R_OPATE_NUM FROM REPORT_MONTH_PERSON_COUNT RMPC,JWT_JYXX JY,T_DWXX DW WHERE RMPC.JYID = JY.JYUSERID AND JY.SSDW = DW.DWID AND RMPC.R_YEAR = 2013 AND RMPC.R_MONTH = 6 AND JY.SSDW LIKE '4102%' ORDER BY RMPC.R_OPATE_NUM DESC) SELECT B.* FROM (SELECT D.*, ROW_NUMBER() OVER(ORDER BY D.R_OPATE_NUM DESC) AS INX FROM REPORT_DATA D ) B WHERE B.INX <=100 ORDER BY B.INX
以下为通过row_number() over(...)删除重复数据的例子,仅供参考:
delete from acc_fundnav
where rowid in (select row1
from (select rowid row1,
row_number() over(partition by HOST_ID order by rowid) lev
from acc_fundnav)
where lev > 1)
RANK():排序的时候跟派名次一样,可以并列2个第一名之后 是第3名
LAG:分组排序后 ,组内后面一条记录减前面一条记录的差,第一条可返回 NULL
BTW: EXPERT ONE ON ONE 上讲的最详细,还有很多相关特性,文档看起来比较费劲
rank()是跳跃排序,有两个第二名时接下来就是第四名(同样是在各个分组内)
dense_rank()l是连续排序,有两个第二名时仍然跟着第三名。
相比之下row_number是没有重复值的
lag(arg1,arg2,arg3):
arg1是从其他行返回的表达式
arg2是希望检索的当前行分区的偏移量。是一个正的偏移量,时一个往回检索以前的行的数目。
arg3是在arg2表示的数目超出了分组的范围时返回的值。
另见:《oracle分析函数技术详解(如 over())》
oracle分析函数技术详解(配上开窗函数over())
Oracle的LAG和LEAD分析函数

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